| 1. |
- Skedung, Lisa, 1980-
(författare)
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Tactile Perception : Role of Friction and Texture
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Tactile perception is considered an important contributor to the overall consumer experience of a product. However, what physical properties that create the specifics of tactile perception, are still not completely understood. This thesis has researched how many dimensions that are required to differentiate the surfaces perceptually, and then tried to explain these dimensions in terms of physical properties, by interconnecting human perception measurements with various physical measurements. The tactile perception was assessed by multidimensional scaling or magnitude estimation, in which methods human participants assign numbers to how similar pairs of surfaces are perceived or to the relative quantity of a specified perceptual attribute, such as softness, smoothness, coarseness and coolness. The role of friction and surface texture in tactile perception was investigated in particular detail, because typically tactile exploration involves moving (at least) one finger over a textured surface. A tactile approach for measuring friction was developed by means of moving a finger over the surfaces, mounted on a force sensor. The contribution of finger friction to tactile perception was investigated for surfaces of printing papers and tissue papers, as well as for model surfaces with controlled topography. The overarching research goal of this thesis was to study, systematically, the role of texture in tactile perception of surfaces.The model surfaces displayed a sinusoidal texture with a characteristic wavelength and amplitude, fabricated by surface wrinkling and replica molding techniques. A library of surfaces was manufactured, ranging in wavelengths from 270 nm up to 100 µm and in amplitudes from 7 nm up to 6 µm. These surfaces were rigid and cleanable and could therefore be reused among the participants. To my knowledge, this is the first time in a psychophysical experiment, that the surface texture has been controlled over several orders of magnitude in length scale, without simultaneously changing other material properties of the stimuli.The finger friction coefficient was found to decrease with increasing aspect ratio (amplitude/wavelength) of the model surfaces and also with increasing average surface roughness of the printing papers. Analytical modeling of the finger’s interaction with the model surfaces shows how the friction coefficient increases with the real contact area, and that the friction mechanism is the same on both the nanoscale and microscale. The same interaction mechanism also explains the friction characteristics of tissue paper. Furthermore, it was found that the perceptions of smoothness, coarseness, coolness and dryness are satisfactorily related to the real contact area at the finger-surface interface. It is shown that it is possible to discern perceptually among both printing papers and tissue papers, and this differentiation is based on either two or three underlying dimensions. Rough/smooth and thin/thick were the two main dimensions of surface feel found for the printing papers, whereas friction and wavelength were strongly related to the perceptual cues employed in scaling the model surfaces. These experimental results support the duplex theory of texture perception, which holds that both a “spatial sense”; used to discriminate the roughest textures from the others, and a “vibration sense”; used to discriminate among the smoother textures, are involved. The perception of what is considered rough and smooth depends on the experimental stimulus context. It is concluded that friction is important for human differentiation of surface textures below about 10 µm in surface roughness, and for larger surface textures, friction is less important or can even be neglected.The finger friction experiments also allowed the following conclusions to be drawn: (i) The interindividual variation in friction coefficients is too large to allow direct comparison; however, the trends in relative friction coefficients for a group of participants are the same. (ii) Lipids are transferred to the test surface of study, and this lowers the friction. (iii) Many of the studies point to a characteristic frequency during sliding of about 30 Hz, which is both characteristic of the resonance frequency of skin and the expected frequency associated with the fingerprints. (iv) The applied load in surface interrogation is in fact regulated in response to the friction force.The limits in tactile perception were indirectly researched by similarity scaling experiments on the model surfaces. Wrinkle wavelengths of 760 nm and 870 nm could be discriminated from untextured reference surfaces, whereas 270 nm could not. The amplitude of the wrinkles so discriminated was approximately 10 nm, suggesting that nanotechnology may well have a role to play in haptics and tactile perception.
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| 2. |
- Skedung, Lisa, et al.
(författare)
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Feeling small : Exploring the Tactile Perception Limits
- 2013
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 3, s. 2617-
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Tidskriftsartikel (refereegranskat)abstract
- The human finger is exquisitely sensitive in perceiving different materials, but the question remains as to what length scales are capable of being distinguished in active touch. We combine material science with psychophysics to manufacture and haptically explore a series of topographically patterned surfaces of controlled wavelength, but identical chemistry. Strain-induced surface wrinkling and subsequent templating produced 16 surfaces with wrinkle wavelengths ranging from 300 nm to 90 mu m and amplitudes between 7 nm and 4.5 mu m. Perceived similarities of these surfaces (and two blanks) were pairwise scaled by participants, and interdistances among all stimuli were determined by individual differences scaling (INDSCAL). The tactile space thus generated and its two perceptual dimensions were directly linked to surface physical properties - the finger friction coefficient and the wrinkle wavelength. Finally, the lowest amplitude of the wrinkles so distinguished was approximately 10 nm, demonstrating that human tactile discrimination extends to the nanoscale.
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| 3. |
- Hermansson, Anne-Marie, 1945, et al.
(författare)
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Innovation genom forskning och långsiktig samverkan mellan akademi och näringsliv
- 2016
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Ingår i: Sveriges entreprenöriella ekosystem - Företag, akademi, politik. - 9789197772846 ; , s. 359-
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Detta kapitel handlar om forskning och innovation inom ett VINN Excellence Centre1 som heter SuMo Biomaterials.2 Författarna har alla varit verksamma vid centrumet, och kapitlet bygger på våra erfarenheter från det arbetet. Vi lyfter fram faktorer som har betydelse för en framgångsrik, långsiktig samverkan mellan akademi och näringsliv.InomSuMo möter företag från helt olika verksamhetsområden, men med likartade vetenskapliga frågeställningar, akademin. Forskningen sker i samverkan och har övergripande betydelse för företagens strategiska mål. Med utgångspunkt från en stark vision utvecklas samarbetsformer för näringslivssamverkan och excellensforskning i kluster över disciplingränser. I kapitlet lyfter vi betydelsen av timing, kommunikation, förväntningar och strategiska förändringar i ett långsiktigt perspektiv. SuMo är finansierat gemensamt av Vinnova, näringslivspartners, SP Food and Bioscience och Chalmers. Centrumet startades i mars 2007 och kommer att avslutas under 2016. Utvecklingen är indelad i fyra faser: initiering och uppstart, forskning i världsklass, implementering samt nyttiggörande. Vårtkoncept och sätt att arbeta bygger mycket på kommunikation och samarbete inom akademin, mellan akademi och näringsliv – men också mellan olika näringslivspartners.
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| 4. |
- Lin, Yuan-Chih, 1987, et al.
(författare)
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Vibrationally induced color shift tuning of photoluminescence in Ce³⁺-doped garnet phosphors
- 2019
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Ingår i: Journal of Materials Chemistry C. - : Royal Society of Chemistry (RSC). - 2050-7534 .- 2050-7526. ; 7:41, s. 12926-12934
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Tidskriftsartikel (refereegranskat)abstract
- A critical challenge in the field of phosphor converted white light emitting diodes (pc-WLEDs) pertains to understanding and controlling the variation of emission color with device temperature. Here we, through a combined photoluminescence (PL) and Raman spectroscopy study of the three garnet type phosphors Ce3+-doped Y3Al5O12 (YAG:Ce3+), Ca3Sc2Si3O12 (CSS:Ce3+), and Sr3Y2Ge3O12 (SYG:Ce3+), show that the color of the PL is systematically shifted upon changing the operation temperature of the phosphor. A general trend is observed that the PL exhibits a red-shift as a function of increasing temperature, until the point at which the vibrational modes of the CeO8 moieties, which induce dynamical tetragonal distortions of the CeO8 dodecahedra, are fully activated. Upon further temperature increase, the PL turns to a blue-shift because of a counteracting and predominating effect of thermal lattice expansion that progressively makes the CeO8 dodecahedra more cubal like. Since this behavior is the result of the symmetry relations intrinsic to the garnet structure, the present mechanism can be generally applicable to materials of this type. It thereby provides a route for tuning the PL of this important class of phosphor materials.
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| 5. |
- Lindgård, Jan, et al.
(författare)
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Nordic Europe
- 2017
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Ingår i: Alkali-aggregate reaction in concrete. - : Taylor & Francis. - 9781315708959 - 9781138027565 ; , s. 277-320, s. 185-211
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 6. |
- Lombardo, Teo, et al.
(författare)
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Artificial Intelligence Applied to Battery Research: Hype or Reality?
- 2022
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Ingår i: Chemical Reviews. - : American Chemical Society (ACS). - 0009-2665 .- 1520-6890. ; 122:12, s. 10899 -10969
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Forskningsöversikt (refereegranskat)abstract
- This is a critical review of artificial intelligence/machine learning (AI/ML) methods applied to battery research. It aims at providing a comprehensive, authoritative, and critical, yet easily understandable, review of general interest to the battery community. It addresses the concepts, approaches, tools, outcomes, and challenges of using AI/ML as an accelerator for the design and optimization of the next generation of batteries - a current hot topic. It intends to create both accessibility of these tools to the chemistry and electrochemical energy sciences communities and completeness in terms of the different battery RD aspects covered.
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| 7. |
- Roos, Sandra, 1977, et al.
(författare)
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A Function‐Based Approach for Life Cycle Management of Chemicals in the Textile Industry
- 2020
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Ingår i: Sustainability. - : MDPI AG. - 2071-1050. ; 12:1273, s. 1-14
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Tidskriftsartikel (refereegranskat)abstract
- Consumer products such as clothes and footwear sometimes contain chemical substances with properties that pose a risk to human health and the environment. These substances, restricted by law or company policy, are in focus for chemicals management processes by textile retailers. However, complex and non‐transparent supply chains, and limited chemical knowledge, makes chemicals management challenging. Therefore, a function‐based approach for life cycle management (LCM) of chemicals was developed, based on results of previous projects and evaluated using a two‐step Delphi process. The resulting approach aims to help retailers identify and substitute hazardous substances in products, and consists of three parts: (i) a function‐based chemicals management concept model for different levels of chemical information within the supply chain, (ii) tools for non‐chemists which explain chemical information, and (iii) a continuous provision of knowledge to stakeholders (e.g., retailers) in a network. This approach is successfully implemented by over 100 retailers in the Nordic countries, providing the textile industry with practical and robust tools to manage and substitute hazardous chemicals in products and production processes. We conclude that the developed approach provides an explicit link, communication, and knowledge sharing between actors in the supply chain, which has proven important in chemicals LCM.
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| 8. |
- Tivander, Johan, 1973, et al.
(författare)
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Emission of chemicals from consumer goods - From product flow data to organic substance emissions to the environment – the case of PVC flooring
- 2011
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Ingår i: 21st Annual Meeting SETAC Europe, Milan, Italy, 2011.
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Konferensbidrag (refereegranskat)abstract
- This case study on PVC flooring investigates the possibilities and barriers to extract and combine Swedish product flow data from Statistics Sweden, in order to derive data detailed enough to populate a developed emission model and execute calculations on total emissions from all PVC flooring in Sweden during one year. A comparison is made, between calculated emissions using either product flow data from Statistics Sweden or from other domestic floor branch sources. At Statistics Sweden, existing databases, published statistics and available methods were used for identifying and illustrating the possible methods and barriers for extraction and combination of product flow data. For calculations of emissions a combined material flow and diffusive mass transfer model was developed and used. This case study shows that the data categories and the methods needed for estimating the accumulated product area exist at Statistics Sweden, in principle, but the data is sometimes too aggregated or too protected to make the calculations on a detailed product category level, as in this case for PVC flooring. Using product flow data from the least aggregated level of the Combined Nomenclature, for PVC flooring, generates calculated emissions three times higher than the emissions calculated from the more specific product flow data from The Swedish Flooring Trade Association. The PVC flooring case study boils down to the facing of a trade off when it comes to national emission assessment of several product categories; using data from Statistics Sweden generates emissions within a reasonable period of time, but with aggregated and in this case, too high values – using branch product flow data generates more accurate emission values but is not a plausible option due to the steep increase in resource demands.
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